Did you tell him how you feel about the outfit? Maybe try talking to him about it. Not to be Captain Obvious here...
 
 I think what you said about the all male, sexist environment is telling. If that's truly it, it's not that he's embarrassed of you, he's actually protecting you! He doesn't want you to become the object of sexual ridicule, nor does he want those guys talking about you behind his back, or worse, while he's standing right there. 
 
 if he still wants you to wear it after talking to him, wear something sexy underneath it. You and your DH might enjoy that thought... frumpy on the outside, sexy underneath 
